Question

Скоротіть дріб x-7/√7+√x

Answer 1

$\displaystyle\bf\\\frac{x-7}{\sqrt{7} +\sqrt{x} } =\frac{\Big(\sqrt{x} \Big)^{2}-\Big(\sqrt{7} \Big)^{2} }{\sqrt{7} +\sqrt{x} } =\frac{\Big(\sqrt{x} +\sqrt{7} \Big)\Big(\sqrt{x} -\sqrt{7}\Big) }{\sqrt{7} +\sqrt{x} } =\sqrt{x} -\sqrt{7}$